Everything You Need to Know about Narcissists, Psychopaths, and Abuse - click on this link: http://www.narcissistic-abuse.com/faq1.html
the narcissistic parent may single out one of his children and encourage the “golden” or “sunshine” child to idolise him, to adore him, to be awed by him, to admire his deeds and capabilities, to learn to blindly trust and obey him, in short to surrender to his charisma and to become submerged in his follies-de-grandeur. The remains of the litter – the chosen one’s brothers and sisters - are ignored, neglected, left to fend off for themselves, or worse: relegated to the role of much-maligned, ridiculed, thwarted, stunted, and hated scapegoats.
Such discriminatory conduct emanates from the narcissistic parent’s projected splitting: a confluence of two psychological defense mechanisms (projection and splitting).
Splitting is a "primitive" defense mechanism. It involves the inability to integrate contradictory qualities, behaviors, and attributes of the same object into a coherent picture. The narcissist regards people around him as either all bad or all good, irredeemably black or lustrously white, implacable foes or undying friends. Splitting results in cycles of idealization followed by devaluation.
But, splitting can also be applied to one's self. Patients with personality disorders often idealize themselves fantastically and grandiosely, only to harshly devalue, hate, and even harm themselves when they fail or are otherwise frustrated.
Projection is another psychological defense mechanism. We all have an image of how we "should be". Freud called it the "Ego Ideal". But sometimes we experience emotions and drives or have personal qualities which don't sit well with this idealized construct. Projection is when we attribute to others these unacceptable, discomfiting, and ill-fitting feelings and traits that we possess. This way we disown these discordant features and secure the right to criticize and chastise others for having or displaying them.
The narcissistic parent splits her personality into good and bad traits, qualities, and dimensions. She projects his or her good aspects, the ones she finds to be acceptable (ego-syntonic) or even desirable onto the golden child who then embodies and reifies everything that’s right and proper in the parent’s personality, an extension of the parent’s grandiosity.
In contradistinction, the traits and qualities of himself or herself that the narcissistic parent finds bad, unacceptable, rejected, or shame-inducing are projected onto and attributed to the scapegoat child, the black sheep of the family, the reject and the outcast who is then rendered a constant reminder of the parent’s shortcomings, a challenge to her fantastic self-perception and, therefore, a permanent narcissistic injury.
(From the book "Malignant Self-love: Narcissism Revisited" by Sam Vaknin - Click on this link to purchase the print book, or 16 e-books, or 3 DVDs with 16 hours of video lectures on narcissists, psychopaths, and abuse in relationships: http://www.narcissistic-abuse.com/thebook.html)